High dynamic range variable fiber-optical attenuator using digital micromirrors and opto-fluidics

To the best of the authors knowledge, proposed is the first variable fiber-optical attenuator (VFOA) using a digital micromirror device (DMD) and an opto-fluidic electronically controlled variable focus lens (ECVFL). The hybrid VFOA uses individually controllable two-state micromirrors of the DMD and the variable focal length capability of the ECVFL to control the amount of light coupled between two fiber ports leading to a high dynamic range VFOA. The demonstrated VFOA at 1545 nm has a 63.5-dB dynamic range, < 0.1-dB resolution, 0.2-dB polarization-dependent loss, 4.9-dB optical loss, and < 100-ms switching time. Applications for the proposed VFOA include use in test and measurement systems.